Vertical exhaust duct for electronic equipment enclosure

ABSTRACT

An electronic equipment enclosure comprises a frame structure formed from a plurality of support posts and at least partially enclosed by a plurality of panels. The panels include at least side, top and back panels defining an enclosure having a top, a bottom and a rear thereof. The top panel includes an opening there through that is rectangular in shape. The equipment enclosure further comprises an exhaust air duct extending upward from the top panel of the enclosure. The exhaust air duct is rectangular in cross-section and is disposed in surrounding relation to, and in fluid communication with, the top panel opening. The exhaust air duct is adapted to segregate hot air being exhausted from the enclosure from cool air entering the enclosure, thereby improving thermal management of the enclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. continuation patent application of,and claims priority under 35 U.S.C. § 120 to, U.S. patent applicationSer. No. 14/793,369, filed Jul. 7, 2015, which '369 applicationpublished as U.S. patent application publication no. US 2015/0319872 A1on Nov. 5, 2015 and issued as U.S. Pat. No. 9,974,198 on May 15, 2018,which '369 application, the application publication thereof, and thepatent issuing therefrom are each incorporated herein by reference intheir entirety, and which '369 application is a U.S. continuation patentapplication of, and claims priority under 35 U.S.C. § 120 to, U.S.patent application Ser. No. 14/280,755, filed May 19, 2014, which '755application published as U.S. patent application publication no. US2014/0323029 A1 on Oct. 30, 2014 and issued as U.S. Pat. No. 9,084,369on Jul. 14, 2015, which '755 application, the application publicationthereof, and the patent issuing therefrom are each incorporated hereinby reference in their entirety, and which '755 application is a U.S.continuation patent application of, and claims priority under 35 U.S.C.§ 120 to, U.S. patent application Ser. No. 13/116,899, filed May 26,2011, which '899 application published as U.S. patent applicationpublication no. US 2011/0287704 A1 on Nov. 24, 2011 and issued as U.S.Pat. No. 8,730,665 on May 20, 2014, which '899 application, theapplication publication thereof, and the patent issuing therefrom areeach incorporated herein by reference in their entirety, and which '899application is a U.S. continuation patent application of, and claimspriority under 35 U.S.C. § 120 to, U.S. patent application Ser. No.12/477,118, filed Jun. 2, 2009, which '118 application published as U.S.patent application publication no. US 2009/0239461 A1 on Sep. 24, 2009and issued as U.S. Pat. No. 7,952,869 on May 31, 2011, which '118application, the application publication thereof, and the patent issuingtherefrom are each incorporated herein by reference in their entirety,and which '118 application is a U.S. divisional patent application of,and claims priority under 35 U.S.C. § 120 to, U.S. patent applicationSer. No. 11/533,362 filed Sep. 19, 2006, which '362 applicationpublished as U.S. patent application publication no. US 2007/0064391 A1on Mar. 22, 2007 and issued as U.S. Pat. No. 7,542,287 on Jun. 2, 2009,which '362 application, the application publication thereof, and thepatent issuing therefrom are each incorporated herein by reference intheir entirety, and which '362 application is a U.S. nonprovisionalpatent application of, and claims priority under 35 U.S.C. § 119(e) to,U.S. provisional patent application No. 60/718,548, filed Sep. 19, 2005,which '548 application is incorporated herein by reference in itsentirety.

Additionally, U.S. patent application publication no. US 2007/0064389A1, published on Mar. 22, 2007 and titled “DUCTED EXHAUST EQUIPMENTENCLOSURE” is incorporated herein by reference in its entirety.

COPYRIGHT STATEMENT

All of the material in this patent document is subject to copyrightprotection under the copyright laws of the United States and of othercountries. The copyright owner has no objection to the facsimilereproduction by anyone of the patent document or the patent disclosure,as it appears in the Patent and Trademark Office patent file or records,but otherwise reserves all copyright rights whatsoever.

BACKGROUND OF THE PRESENT INVENTION Field of the Present Invention

The present invention relates generally to cabinets for rack-mountcomputer and data storage equipment, and, in particular, to thermalmanagement of cabinets for rack-mount computer and data storageequipment.

Background

Racks, frames and cabinets for mounting and storing computer and otherelectronic components or equipment have been well known for many years.Racks and frames are typically simple rectangular frameworks on whichelectronic components may be mounted, or on which other mountingmembers, such as shelves or brackets, may be mounted which in turn maysupport the electronic components. Cabinets are typically frames onwhich panels or doors, or both, are hung to provide aestheticimprovement, to protect the components from external influences, toprovide security for the components stored inside, or for other reasons.

Racks, frames and cabinets have been built in many different sizes andwith many different proportions in order to best accommodate thecomponents which they are designed to store. Components stored in theseenclosures may include audio and video equipment and the like, but quitefrequently include computer equipment and related peripheral devices.These components typically include housings enclosing internal operativeelements.

As is also well known, the electronic equipment mounted therein tends togenerate large amounts of thermal energy that needs to be exhausted awayfrom the equipment effectively in order to maintain the equipment inproper operating order or to prevent damage thereto. The problem can beespecially significant when the components are enclosed in cabinets,because thermal energy generated thereby can concentrate within theequipment enclosure and cause the components to overheat and shut down.As equipment becomes more densely packed with electronics, thequantities of thermal energy have continued to increase in recent years,and thermal energy management has become a significant issue confrontingtoday's rack, cabinet, frame and enclosure manufacturers, themanufacturers of the electronic equipment, and the users of suchequipment.

Typically, multiple racks, frames, cabinets, and the like (sometimescollectively referred to hereinafter as “enclosures”) are housedtogether in a data center. Because of the overheating problem, andparticularly with multiple enclosures being placed in a single room orother enclosed space, thermal management of the data center is veryimportant. A goal of data center thermal management is to maximize theperformance, uptime and life expectancy of the active components beinghoused in the data center. This goal is generally accomplished bymanaging the cold air delivered to each component such that the internaltemperature of the component does not exceed the manufacturer's maximumallowable operating temperature. Preferably, the cold air delivered tothe component is at or below the manufacturer's recommended temperatureand in sufficient volume to meet the airflow requirements of thecomponent, which are typically measured in cubic feet per minute (CFM).

A common type of operating environment for enclosures and the equipmentmounted therein is known as a “raised floor” system, wherein theenclosures are supported on a heavy-duty mechanical floor that isinstalled above the actual floor of the room at a given elevation. Onesignificant advantage of this approach is that cables, wires, waterpipes, and other utility connections may be routed to and from theenclosures via the space beneath the floor, thereby leaving the topsurface of the raised floor clear for locating enclosures and traversalby users. Another significant advantage, however, is that the spacebeneath the top surface of the raised floor serves as a plenum throughwhich cool air may likewise be distributed to the enclosures. Throughopen tiles or perforations or ventilations in the tiles comprising thesurface of the raised floor, this cool air may be supplied to theenclosures and used to cool the equipment inside.

Unfortunately, the use of perforated floor tiles, typically locateddirectly in front of enclosures to try to cause a maximum amount of coolair to be directed into the enclosures and not merely lost to theambient room, have been found to be insufficient in cooling theequipment within the enclosures to the desired degree. Thus, a number oftechniques and devices have been developed in recent years to moreefficiently utilize the capabilities of the Computer Room AirConditioner (“CRAC”) and to put the available cool air to the mostefficient use possible. Among others, these include improved strategiesinvolving perforated panels, such as those described in thecommonly-assigned U.S. Provisional Patent Application No. 60/725,511,filed Oct. 10, 2005 and entitled “EFFICIENT USE OF PERFORATED PANELS INELECTRONIC EQUIPMENT CABINETS,” and also improved cool air distributionstrategies, such as those described in the commonly-assigned U.S.Provisional Patent Application No. 60/743,148, filed Jan. 20, 2006 andentitled “INTERNAL AIR DUCT,” the entirety of each of which isincorporated herein by reference.

The supply of cool air to the raised floor plenum, and the transfer ofthermal energy from the electronic equipment, is conventionally handledby the CRAC. Airflow through the plenum and into the enclosuresgenerally relies solely or at least primarily on the air pressuredifferential as measured between the raised floor plenum and the ambientroom. However, active means are often used to push or pull heated airout of the enclosures.

For a particular component, thermal energy is transferred from itshousing using forced air convection. More specifically, internal fansdraw or push air through the housing from front-to-rear over the heatedinternal elements within the housing. The air absorbs the thermal energyfrom the internal elements and carries it away as it exits the housing.

Airflow through a particular component housing is primarily controlledby the internal fan installed by the manufacturer. While it is possibleto reduce this throughput by constricting air flow through an enclosure,it is difficult to appreciably increase the airflow through a componenthousing.

In addition, the rate of transfer of thermal energy from the housingdoes not change very much for different intake air temperatures.Lowering the intake air temperature reduces the temperature of theprocessor(s) inside of the component, but the temperature change and thetotal cooling taking place for the component does not change for aconstant airflow. Therefore, any enclosure that does not choke theairflow through the component mounted inside and that preventsrecirculation should effectively dissipate most, if not all, of thethermal energy generated by the component.

Recent conventional thinking for the thermal management of data centersinvolves the use of an approach commonly referred to as the HotAisle/Cold Aisle approach. In this strategy, cold air aisles aresegregated from hot air aisles by enclosures being positioned betweenthem such that cold air aisles are in front of rows of enclosures andhot air aisles are behind these rows of enclosures. In this approach,the cold air and hot air aisles alternate. Ideally, air enters theenclosure from the cold air aisles and is exhausted from the enclosureinto the hot air aisles.

This approach works well in low to medium density data centerapplications. However, it does not perform well in many medium densityapplications and can not support high density applications withoutextreme discipline and additional air flow management devices outside ofthe enclosures to prevent hot exhaust recirculation into the cold aisle.

Further, Hot Aisle/Cold Aisle data center environments typically do notoperate at ideal conditions. Two common problems that affect thermalmanagement in general, and Hot Aisle/Cold Aisle in particular, arerecirculation and bypass. Recirculation occurs when hot exhaust airtravels back into the component intake air stream. Recirculation canoccur for a single component or for an entire enclosure. When thisoccurs, the exhaust airflow raises intake air temperatures and causescomponents to run at higher operating temperatures. Bypass occurs whencold source air bypasses the active component and travels directly intothe hot exhaust air stream. Similarly to recirculation, bypass may occurfor a single component or for a whole enclosure. Because cold source airis bypassing the active component, the air is not serving its intendedpurpose of transferring thermal energy away from the active component.As such, the bypassing air is essentially wasted, and the activecomponent retains its thermal energy until additional cold source aircontacts the active component thereby transferring the thermal energyaway from the component. Based on the foregoing, it is readily apparentthat bypass wastes energy. In addition, bypass contributes to humiditycontrol problems, and can indirectly contribute to recirculation. Underideal circumstances, all recirculation and bypass airflow can beeliminated.

Hot Aisle/Cold Aisle is a well-principled thermal management approach,i.e., segregating the cold source air in front of enclosures and hotexhaust air behind them does work. Unfortunately, maintaining thesegregation is difficult. In order to maintain proper segregation, theairflow delivered to each enclosure must roughly equal the airflowrequired by all of the active components in each enclosure. In addition,strict discipline and careful airflow balancing are required to maintainthis ideal operating condition in higher density data centerenvironments. While an initial installation may realize these idealconditions, moves, adds and changes, along with the demands forconstantly monitoring and rebalancing, frequently make maintaining thisideal operating condition impractical, if not outright impossible.

For example, one known airflow balancing technique employs variablespeed fans that are carefully monitored and controlled using appropriatecontrol methodologies. A drawback to the controlled variable speed fanapproach is the unpredictable nature of components, particularly serverusage. For example if a server is suddenly heavily burdened by aparticular software application, the server heats up, perhaps morequickly than expected, or more than can be handled quickly by acorresponding variable fan. The fan then quickly increases in speed inan attempt to respond to the sudden drastic increase in temperature ofthe server. The fan may not be able to sufficiently supply cooling airto the suddenly overheated server, and even if it is, such heatbalancing procedure is difficult, at best, to manage. It would be betterto avoid dependence on such a reactive approach to thermal management.

Cylindrical exhaust ducts have been added to enclosures in an effort toalleviate thermal management issues such as recirculation and bypass.The exhaust ducts generally extend upwardly away from a top surface ofthe enclosure near the rear of the enclosure and provide a path for hotexhaust air to be expelled. While available exhaust ducts are operativefor their intended purpose, an improved design thereof would further aidin alleviating thermal management issues. In addition, it has been foundthat heated air tends to pool or collect in portions of the interior ofenclosures rather than be guided to the exhaust ducts.

As such, a need exists for an improved design of exhaust ducts forcomponent storage enclosures. Further, additional thermal managementfeatures are needed in these enclosures. This, and other needs, areaddressed by one or more aspects of the present invention.

SUMMARY OF THE PRESENT INVENTION

The present invention includes many aspects and features. Moreover,while many aspects and features relate to, and are described in, thecontext of enclosures for storage of electronic equipment, the presentinvention is not limited to use only in enclosures for storage ofelectronic equipment, as will become apparent from the followingsummaries and detailed descriptions of aspects, features, and one ormore embodiments of the present invention.

Broadly defined, the present invention according to one aspect includesan electronic equipment enclosure comprising a frame structure formedfrom a plurality of support posts and at least partially enclosed by aplurality of panels. The panels include at least side, top and backpanels defining an enclosure having a top, a bottom and a rear thereof.The top panel includes an opening there through that is rectangular inshape. The equipment enclosure further comprises an exhaust air ductextending upward from the top panel of the enclosure. The exhaust airduct is rectangular in cross-section and is disposed in surroundingrelation to, and in fluid communication with, the top panel opening. Theexhaust air duct is adapted to segregate hot air being exhausted fromthe enclosure from cool air entering the enclosure, thereby improvingthermal management of the enclosure.

In a feature of this aspect, the top panel opening is disposed towardthe rear of the top panel. In accordance with this feature, the toppanel opening is disposed substantially adjacent the back panel of theenclosure. With regard to this feature, the dimensions of therectangular cross-section of the exhaust air duct are substantiallysimilar to the dimensions of the top panel opening.

In another feature, the top panel opening is disposed toward the rear ofthe enclosure. In an additional feature, the exhaust air duct isself-supporting. In yet another feature, the exhaust air duct is adaptedto be connected to a separate overhead structure in a room. With regardto this feature, the exhaust air duct is adapted to be connected to areturn air duct. With further regard to this feature, the exhaust airduct has a top edge and a mounting flange extending around the peripheryof the top edge for connection to a separate overhead structure in aroom.

In yet another feature, the height of the exhaust air duct isadjustable, thereby adjusting the distance to which the exhaust air ductextends above the top panel of the enclosure. With regard to thisfeature, the exhaust air duct includes a first rectangular open-endedduct section that nests inside a second rectangular open-ended ductsection, wherein the first duct section may be telescopically withdrawnfrom the second duct section.

In a further feature, the back panel is generally air-impervious toprevent heated air from escaping there through. In accordance with thisfeature, the back panel is a door panel that is connected at aconnection point to the frame structure. Seals are disposed at theconnection point between the back door panel and the frame structure. Infurtherance of this feature, the seals are brackets. With regard to thisfeature, the seals are metal. It is preferred that rubber or foamgaskets are included with the seals.

In an additional feature, the plurality of panels includes a bottompanel that has a brush opening arranged therein.

Broadly defined, the present invention according to another aspectincludes an electronic equipment enclosure comprising a frame structureformed from a plurality of support posts and at least partially enclosedby a plurality of panels. The panels include at least side, top and backpanels defining an enclosure having a top, a bottom and a rear thereof.The top panel includes an opening there through. The equipment enclosurefurther comprises an exhaust air duct extending upward from the toppanel of the enclosure. The exhaust air duct is disposed in generallysurrounding relation to, and in fluid communication with, the top panelopening. The enclosure further comprises an air diverter, disposed nearthe rear of the enclosure and angled upward to redirect, toward the topof the enclosure, heated air moving rearward through the enclosure. Theexhaust air duct and the air diverter cooperate to segregate hot airbeing exhausted from the enclosure from cool air entering the enclosure,thereby improving thermal management of the enclosure.

In a feature of this aspect, the top panel opening is rectangular inshape. In another feature, the top panel opening is disposed toward therear of the top panel. In an additional feature, the top panel openingis disposed substantially adjacent the back panel of the enclosure. Inaccordance with this feature, the exhaust air duct is rectangular incross-section, and the dimensions of the rectangular cross-section ofthe exhaust air duct are substantially similar to the dimensions of thetop panel opening.

In yet another feature, the top panel opening is disposed toward therear of the enclosure. In a further feature, the exhaust air duct isself-supporting. In still a further feature, the exhaust air duct isadapted to be connected to a separate overhead structure in a room. Inaccordance with this feature, the exhaust air duct is adapted to beconnected to a return air duct. With further regard to this feature, theexhaust air duct has a top edge and a mounting flange extending aroundthe periphery of the top edge for connection to a separate overheadstructure in a room.

In an additional feature, the height of the exhaust air duct isadjustable, thereby adjusting the distance to which the exhaust air ductextends above the top panel of the enclosure. In furtherance of thisfeature, the exhaust air duct includes a first rectangular open-endedduct section that nests inside a second rectangular open-ended ductsection, wherein the first duct section may be withdrawn from the secondduct section by a predetermined amount.

In another feature, the back panel is generally air-impervious toprevent heated air from escaping there through. With regard to thisfeature, the back panel is a door panel that is connected at aconnection point to the frame structure. Seals are disposed at theconnection point between the back door panel and the frame structure.With further regard to this feature, the seals are brackets. It ispreferred that the seals are metal. It is further preferred that rubberor foam gaskets are included with the seals.

In still yet another feature, the plurality of panels includes a bottompanel that has a brush opening arranged therein.

Broadly defined, the present invention according to yet another aspectincludes an exhaust air duct adapted to segregate hot air beingexhausted from an electronic equipment enclosure from cool air enteringthe enclosure, thereby improving thermal management of the enclosure,wherein the exhaust air duct includes four panels joined at side edgesthereof to form a rectangular shaped exhaust duct. Each of at least twoof the panels has a flange at a bottom edge thereof such that theexhaust air duct has a flange around a bottom periphery thereof.

In a feature of this aspect, each of all four of the panels has a flangeat a bottom edge such that the exhaust air duct has a flange around abottom periphery thereof. In another feature, the panels are constructedof a material that is self-supporting. In yet another feature, an upperend thereof is adapted to be connected to a separate overhead structurein a room. In accordance with this feature, the upper end thereof isadapted to be connected to a return air duct. With regard to thisfeature, the upper end thereof has a top edge and a mounting flangeextending around the periphery of the top edge for connection to aseparate overhead structure in a room.

In an additional feature, the height of the exhaust air duct isadjustable, thereby adjusting the distance to which the exhaust air ductextends above the top panel of the enclosure. With regard to thisfeature, the exhaust air duct includes a first rectangular open-endedduct section that nests inside a second rectangular open-ended ductsection, wherein the first duct section may be telescopically withdrawnfrom the second duct section. In accordance with this feature, thetelescopically withdrawn duct section is self-supporting. Further inaccordance with this feature, the telescopically withdrawn duct sectionmay be affixed to the second duct section at a user-controlled verticaldisposition relative to the second duct section. It is preferred that atleast one of the duct sections includes a plurality of columns ofevenly-spaced openings adapted to facilitate the connection of the twoduct sections together to effectuate the user-controlled verticaldisposition.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, embodiments, and advantages of the present inventionwill become apparent from the following detailed description withreference to the drawings, wherein:

FIG. 1 is a rear isometric view of a ducted exhaust equipment enclosurein accordance with a preferred embodiment of the present invention;

FIG. 2 is a left plan view of the ducted exhaust equipment enclosure ofFIG. 1;

FIG. 3 is a rear plan view of the ducted exhaust equipment enclosure ofFIG. 1;

FIG. 4 is a front plan view of the ducted exhaust equipment enclosure ofFIG. 1;

FIG. 5 is a top plan view of the ducted exhaust equipment enclosure ofFIG. 1;

FIG. 6 is a bottom plan view of the ducted exhaust equipment enclosureof FIG. 1;

FIG. 7 is a left side cross-sectional view of the ducted exhaustequipment enclosure of FIG. 1, taken along the line 7-7;

FIG. 8 is an isometric view of the exhaust air duct of FIG. 1;

FIG. 9 is an isometric view of an exemplary telescoping exhaust air ductfor use with the ducted exhaust equipment enclosure of FIG. 1;

FIG. 10 is a front orthogonal view of the scoop of FIG. 7;

FIG. 11 is a rear isometric view of the ducted exhaust equipmentenclosure of FIG. 1, shown installed on a raised floor;

FIG. 12 is a side cross-sectional view of the ducted exhaust equipmentenclosure of FIG. 11, taken along the line 12-12; and

FIG. 13 is a schematic illustration of a series of ducted exhaustequipment enclosures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As a preliminary matter, it will readily be understood by one havingordinary skill in the relevant art (“Ordinary Artisan”) that the presentinvention has broad utility and application. Furthermore, any embodimentdiscussed and identified as being “preferred” is considered to be partof a best mode contemplated for carrying out the present invention.Other embodiments also may be discussed for additional illustrativepurposes in providing a full and enabling disclosure of the presentinvention. Moreover, many embodiments, such as adaptations, variations,modifications, and equivalent arrangements, will be implicitly disclosedby the embodiments described herein and fall within the scope of thepresent invention.

Accordingly, while the present invention is described herein in detailin relation to one or more embodiments, it is to be understood that thisdisclosure is illustrative and exemplary of the present invention, andis made merely for the purposes of providing a full and enablingdisclosure of the present invention. The detailed disclosure herein ofone or more embodiments is not intended, nor is to be construed, tolimit the scope of patent protection afforded the present invention,which scope is to be defined by the claims and the equivalents thereof.It is not intended that the scope of patent protection afforded thepresent invention be defined by reading into any claim a limitationfound herein that does not explicitly appear in the claim itself.

Thus, for example, any sequence(s) and/or temporal order of steps ofvarious processes or methods that are described herein are illustrativeand not restrictive. Accordingly, it should be understood that, althoughsteps of various processes or methods may be shown and described asbeing in a sequence or temporal order, the steps of any such processesor methods are not limited to being carried out in any particularsequence or order, absent an indication otherwise. Indeed, the steps insuch processes or methods generally may be carried out in variousdifferent sequences and orders while still falling within the scope ofthe present invention. Accordingly, it is intended that the scope ofpatent protection afforded the present invention is to be defined by theappended claims rather than the description set forth herein.

Additionally, it is important to note that each term used herein refersto that which the Ordinary Artisan would understand such term to meanbased on the contextual use of such term herein. To the extent that themeaning of a term used herein—as understood by the Ordinary Artisanbased on the contextual use of such term—differs in any way from anyparticular dictionary definition of such term, it is intended that themeaning of the term as understood by the Ordinary Artisan shouldprevail.

Furthermore, it is important to note that, as used herein, “a” and “an”each generally denotes “at least one,” but does not exclude a pluralityunless the contextual use dictates otherwise. Thus, reference to “apicnic basket having an apple” describes “a picnic basket having atleast one apple” as well as “a picnic basket having apples.” Incontrast, reference to “a picnic basket having a single apple” describes“a picnic basket having only one apple.”

When used herein to join a list of items, “or” denotes “at least one ofthe items,” but does not exclude a plurality of items of the list. Thus,reference to “a picnic basket having cheese or crackers” describes “apicnic basket having cheese without crackers”, “a picnic basket havingcrackers without cheese”, and “a picnic basket having both cheese andcrackers.” Finally, when used herein to join a list of items, “and”denotes “all of the items of the list.” Thus, reference to “a picnicbasket having cheese and crackers” describes “a picnic basket havingcheese, wherein the picnic basket further has crackers,” as well asdescribes “a picnic basket having crackers, wherein the picnic basketfurther has cheese.”

Referring now to the drawings, in which like numerals represent likecomponents throughout the several views, the preferred embodiments ofthe present invention are next described. The following description ofthe preferred embodiment(s) is merely exemplary in nature and is in noway intended to limit the invention, its application, or uses.

FIGS. 1-6 are various views of a ducted exhaust equipment enclosure 10in accordance with a preferred embodiment of the present invention. Moreparticularly, FIG. 1 is a rear isometric view of such a ducted exhaustequipment enclosure 10, and FIGS. 2-6 are a left plan view, rear planview, front plan view, top plan view and bottom plan view, respectively,of the ducted exhaust equipment enclosure of FIG. 1. As shown therein,the ducted exhaust equipment enclosure 10 includes a four post framestructure 12 having panels 32,34,36,38,40, more fully describedhereinbelow, partially enclosing the enclosure 10, attached thereto andan exhaust air duct 14 extending upwardly from the top of the enclosure10.

The four post frame structure 12 may be of conventional design andconstruction. As shown and described, the four post frame structure 12includes four vertical support posts 16, upper and lower front crossmembers 18, upper and lower rear cross members 20 and two pairs of upperand lower side cross members 22. Each vertical support post 16 includesa plurality of cross member attachment apertures at each end. Two of thevertical support posts 16 are connected together at their upper andlower ends by the upper and lower front cross members 18, respectively,and the other two support posts 16 are connected together at their upperand lower ends by the upper and lower rear cross members 20,respectively. The front cross members 18 and their respective supportposts 16 thus define a front frame 24, and the rear cross members 20 andtheir respective support posts 16 define a rear frame 26. The front andrear frames 24,26 may then be connected together at their respectivecorners by the upper and lower side cross members 22.

Any known connection means may be used to join the various memberstogether. One example of such a connection means is illustrated in FIGS.1-6. Although not illustrated herein, at least one other example ofconventional connection means is described in commonly-assigned U.S.Pat. No. 6,185,098, the entirety of which is incorporated herein byreference. Although likewise not illustrated herein, the precision andthe stability of each of the corners of at least some types of four postframe structures may be enhanced by utilizing a self-squaring cornerattachment bracket such as that disclosed by the commonly-assigned U.S.Pat. No. 5,997,117 entitled “RACK FRAME CABINET,” the entirety of whichis hereby incorporated by reference.

It will be evident to the Ordinary Artisan that other structures may beused to form a frame structure on which panels may be mounted to form anenclosure. For example, in at least one embodiment (not illustrated), aframe structure may be formed from only two support posts.

FIG. 7 is a left side cross-sectional view of the ducted exhaustequipment enclosure 10 of FIG. 1, taken along the line 7-7. As perhapsbest seen in FIG. 7, the four post frame structure 12 further comprisesthree pairs of horizontal mounting rails 28. Each horizontal mountingrail 28 includes a slot running substantially its entire length. Inaddition, three pairs of vertical mounting rails 30 are mounted to thehorizontal mounting rails 28 using suitable fasteners held in place inthe slots of the horizontal mounting rails 28. Each vertical mountingrail 30 preferably includes a series of threaded mounting apertures,arranged in evenly-spaced sets, extending along substantially its entirelength for use in mounting electronic components, peripheral devices,cable brackets, additional mounting members, or the like thereto. It iscontemplated that the number of horizontal and vertical mounting railsis variable. For example, an enclosure may include two horizontalmounting rails and two vertical mounting rails. Further, although thenumber of horizontal mounting rails is equal to the number of verticalmounting rails in the two examples mentioned herein, it is not necessarythat the number of mounting rails be equal. It is further contemplatedthat, alternatively, each horizontal mounting rail may include one ormore rows of mounting apertures extending along its length.

With particular reference to FIGS. 1 and 6, the enclosure 10 includes aright panel 32, a left panel 34, a bottom panel 36, a top panel 38 and aback panel 40, all attached to the frame structure 12, which partiallyenclose the enclosure 10. The right and left panels 32,34 are similarlydimensioned and the bottom and top panels 36,38 are similarlydimensioned, though differently constructed. As is shown in FIG. 4, afront of the enclosure 10 is open, therefore, the enclosure 10 is notcompletely enclosed. In a contemplated variation, the enclosure 10 mayinclude a perforated or ventilated front panel (not illustrated). TheOrdinary Artisan will understand that either variation of a front panelis operative to provide a path for air to enter the enclosure 10 forcooling the components contained therein. Further, although in theillustrated arrangement the back panel 40 is, in fact, a lockable door,it will be evident to the Ordinary Artisan that alternatively othertypes of doors and panels may be substituted for the various panels, andthat one or more of the illustrated panels (such as one or both sidepanels 32,34) may in some cases be omitted altogether (such as in a rowof two or more adjoining enclosures 10). It is, however, preferred thatthe back panel be solid, i.e., substantially air impervious, so thatheated air is prevented from escaping through the door as furtherdescribed hereinbelow. Any known connection means may be used to jointhe panels to the frame structure 12, including the back door panel 40.

With reference to FIG. 5, the top panel 38 of the enclosure 10 includesa rectangular shaped opening 42 disposed adjacent the rear of theenclosure 10. The opening 42 is an exhaust opening and is intended toprovided an outlet for air being exhausted from the enclosure 10, asfurther described hereinbelow.

As perhaps best seen in FIG. 1, the opening 42 of the top panel 38 issurrounded by, and in fluid communication with, the exhaust air duct 14.FIG. 8 is an isometric view of the exhaust air duct 14 of FIG. 1. Theexhaust air duct 14 is generally rectangular in cross-section and hasfour generally planar panels 54,56 of substantially similar lengthforming a body thereof. The width of the front and rear panels 54 isselected to correspond to the width of the enclosure 10, with the widthbeing as wide as possible and still be mountable to the top of theenclosure 10. The width of the side panels 56 of the exhaust air duct 14are dependent on the length or depth of the enclosure 10 and in somecases the distance between the rear of equipment mounted inside and therear of the enclosure 10. The panels 54,56 are preferably constructed ofa smooth, stiff material providing a low-restriction exhaust air duct 14that is self-supporting. Examples include, but are not limited to,aluminum or steel of a sufficient gauge to permit self-support.Significantly, unlike corrugated air ducts, the smooth nature of thematerial provides a surface that encourages, rather than hinders airflow. The exhaust air duct 14 is open at a bottom and top thereof toallow for unencumbered air passage there through. The rectangularcross-section and large size of the exhaust air duct 14 provides for aconsiderably larger cross-section than that of conventional cylindricalexhaust air ducts, and thus much greater flow-through. Further, thecross-section of the exhaust air duct 14 is therefore substantially thesame as that of the top panel opening 42 to allow air to flow from thetop panel opening 42 through the exhaust air duct 14 withoutencountering any obstruction. The exhaust air duct 14 segregates the hotexhaust air from cool air entering the enclosure 10 by directing it upand away from the enclosure 10.

Each of the panels 54,56 of the exhaust air duct 14 has a flange 46 at abottom edge 48 thereof for attachment to the top panel 38 of theenclosure 10 around a rim 50 of the top panel opening 42. A top edge 52of the exhaust air duct 14 may be connected to a room's return air duct,as shown schematically in FIG. 12. As will be evident to the OrdinaryArtisan, it may be desirable to include additional features at the topedge 52 of the duct 14, such as a mounting flange (not shown) extendingaround the periphery thereof, to facilitate such connection. However,the self-supporting nature of the exhaust air duct 14 enables it to bepositioned upright without any support from such a return air duct.Still more preferably, the height of exhaust air duct 14 may beadjustable for use in rooms with varying ceiling heights. In order tofacilitate such adjustability, the exhaust air duct 14 may have atelescoping design or some other design capable of adjustability. Suchadjustability may be further enhanced by the self-supporting nature ofthe exhaust air duct 14. In contrast, conventional air ducts must beattached at either end to a support because they are notself-supporting, therefore, conventional air ducts lose the freedom ofadjustability that is available in the exhaust air duct 14 of thepresent invention.

FIG. 9 is an isometric view of an exemplary telescoping exhaust air duct98 for use with the ducted exhaust equipment enclosure of FIG. 1. Thetelescoping duct 98 comprises two duct sections 100,102 having asomewhat similar construction to that described above for the exhaustair duct 14. More particularly, both duct sections 100,102 areopen-ended and have a rectangular cross-section defined by front andback panels and left and right panels. The telescoping duct 98 includesa first duct section 100 with a rectangular cross-section that isslightly smaller in cross-section than a second duct section 102, withinwhich the first duct section 100 nests. The telescoping duct 98preferably includes a means for fixing the total height of the duct 98once it has been adjusted, i.e., once the relation of the first ductsection 100 to the second duct section 102 has been decided. In thepresent embodiment, each of two opposing panels of the first ductsection 100 includes a pair of openings (not shown), with each openingbeing disposed near opposite lower corners of the panels. These openingsmay be disposed in front and back panels or left and right panels,depending on the orientation of the telescoping duct 98 when it isinstalled in the enclosure 10. Each of two opposing panels of the secondduct section 102 includes a pair of columns of openings 106, preferablyevenly-spaced, that are disposed near side edges of the panels. When thetelescoping duct 98 is assembled, the opposing panels of the first ductsection 100 having the pair of openings described above are aligned withthe opposing panels of the second duct section 102 having the columns ofcorresponding openings 106. In this arrangement, the openings of thefirst duct section 100 may be adjusted vertically until the openings arealigned with a desired set of openings 106 of the second duct section102. Thus, the first duct section 100 may be moved upwardly ordownwardly, thereby extending or retracting the height of thetelescoping duct 98, until the desired height is reached. At this point,the four openings of the first duct section 100 should be aligned withfour openings 106 of the second duct section 102 that lie in the samehorizontal plane. Bolts or other fasteners 108, or some other similarlyfunctioning connection means (such as a spring-loaded pin or the like)may be inserted through the aligned openings of the first 100 and secondduct sections 102 to fix the height of the telescoping duct 98. If it issubsequently desired to adjust the height, the bolts 108 may be removedand the first duct section 100 slid upwardly or downwardly until the newdesired height is reached.

In the telescoping duct 98, the second duct section 102 may include aflange 110 at bottom edges of the opposing panels that do not have thecolumns of openings 106. The telescoping duct 98 may be connected to theenclosure 10 using the flanges 110. In addition, the panels that includethe columns of openings 106 may have a bottom edge that extends slightlylower than the bottom edges of the other panels. These bottom edges mayextend into the opening 42 of the top panel 38 of the enclosure 10. Aswill be evident to the Ordinary Artisan, the dispositions of theseelements may be changed as desired.

Referring back to FIG. 8, front and back panels 54 of the exhaust airduct 14 include additional flanges 58 at side edges thereof. The flanges58 of the front and back panels 54 fold around side edges of the rightand left panels 56 at the corners of the rectangular shaped exhaust airduct 14. Any known connection means, such as screws, may be used to jointhe exhaust air duct panels 54,56 using the flanges 58 of the front andback panels 54. This arrangement further improves the rigidity of theexhaust air duct 14.

Because of the positioning of the exhaust air duct 14 on the enclosure10, the back panel 54 thereof is nearly vertically aligned with avertical plane of the back panel 40 of the enclosure 10. Further,because the rectangular shape of the exhaust air duct 10 is similar tothe rectangular shape of the back of the enclosure 10, exhaust air flowsfreely through the exhaust air duct 14. In contrast, in a conventionalcylindrical exhaust air duct, air from the back of the angularly shapedenclosure, particularly the corners of the enclosure, must take atortuous and winding path in order to exit the server enclosure. Thisrelatively complex air flow scheme decreases the rate at which and theamount of air that may exit the enclosure. Further because therectangular exhaust air duct 14 is similar in shape to the back of theenclosure 10 itself, it can be made larger in cross-section thanconventional cylindrical ducts, thus allowing for more airflow throughthe exhaust air duct 14. Accordingly, the rectangular cross-section ofthe exhaust air duct 14 facilitates increased transfer of thermal energyfrom the enclosure 10 in comparison to conventional enclosures withconventional exhaust air ducts 14 because of the increased exhaust airflow rate and the decreased resistance to flow permitted by the size,shape and smooth panels of the rectangular exhaust air duct 14.

As shown in FIG. 13, the exhaust air duct 14 may be connected to aroom's exhaust air removal system, which commonly includes a return airduct. However, the exhaust air duct 14 does not have to be connected toa return air duct. The enclosure 10 may vent directly into the room intowhich the enclosure 10 is placed. This approach is more useful in roomsthat have high ceilings into which to vent the hot air, however, thenatural buoyancy of hot air will keep the hot vented air at or near thetop of the room into which it is vented.

The enclosure 10 may be used in connection with a hot aisle/cold aisleconfiguration of a data center or computer room. If a series ofenclosures 10 are arranged in a row in such configuration, the exhaustair ducts 14 form a vertical wall rising from the tops of the enclosures10 due to their size and shape. This vertical wall may serve as abarrier to recirculation, thereby improving the performance of the hotaisle/cold aisle thermal system.

As seen in FIG. 7, the enclosure 10 may also include an air flowdirector or air diverter 60 located near the bottom of the enclosure 10and generally directly beneath the opening 42 for the exhaust air duct14. FIG. 10 is a front orthogonal view of the air diverter 60 of FIG. 7.As shown therein, the air diverter 60 comprises a planar panel 62 havinga series of creases or bends therein so as to create a generallyscoop-shaped structure. Preferably, the creases or bends are generallyregularly spaced such that cross-section of the structure approximatesan arc, as evident from FIG. 7. Of course, it will be evident to theOrdinary Artisan that alternatively the structure may, in fact, have auniformly curved (non-planar) cross-section, but the use of a planarpanel 62 that is bent or creased to approximate an arc cross-section mayimprove manufacturability. Further, it will be evident that while thepresent embodiment comprises a generally curved structure, it isimportant to note that the air diverter 60 may comprise any shape thatcreates a scoop effect for air flowing through the enclosure 10.

The air diverter 60 has a width that at its maximum is substantially thesame as the distance between the horizontal mounting rails 28. The airdiverter 60 includes a pair of wing elements 80 disposed opposite oneanother on opposite side edges of the air diverter 60. The wing elements80 extend beyond the side edges of the air diverter 60 such that theyessentially span the entire distance between the horizontal mountingrails 28. A bottom edge 64 of the air diverter 60 has a flange 66 forconnecting the air diverter 60 to the bottom panel 36 of the enclosure10. Any known connection means may be used to join the air diverter 60to the bottom panel 36 of the enclosure 10. Alternatively, the airdiverter 60 may be left unfastened to the bottom panel 36, therebypermitting the air diverter 60 to be relocated forward or backward fromthe location illustrated in FIG. 7. If left unfastened, it is useful toinclude means for preventing the air diverter 60 from being rotatedupward by the forces applied by cables as described hereinbelow. Onesuch means is a small protuberance 81 that may be included on the wingelements and that hooks underneath the horizontal mounting rails 28 towhich the diverter 60 is attached as described below.

The air diverter 60 further includes a “U”-shaped channel member 68disposed at a top edge 70 thereof. The channel member 68 includes a topsurface 72 and two side surfaces 74 extending from the top surface 72.One of the side surfaces 74 is attached to the top edge 70 of the airdiverter 60. The channel member 68 is arranged such that the top surface72 thereof extends away from a front surface 76 of the air diverter 60.The channel member 68 provides rigidity for the air diverter 60.

The channel member 68 also serves another purpose, as next described. Ascan be seen in FIG. 7, the enclosure 10 includes a cable openings 96located behind and beneath the air diverter 60 and in the top panel 38.Cables (not shown) used to power components or supply data to or fromcomponents stored in the enclosure 10 can be routed through the cableopenings 96. In particular, it is contemplated that a substantial numberof cables may be disposed between the back panel 40 of the enclosure 10and the air diverter 60, and in fact, the back of the air diverter 60may aid in forcing the cables toward the rear of the enclosure 10. Suchcables may exert a considerable amount of tension on the back of the airdiverter and particularly on the uppermost and/or rearmost surfaces ofthe channel member 68. If these surfaces are rough, they couldpotentially cause considerable chafing on the surfaces of the cables,thereby damaging them. Advantageously, because the distal edge of thechannel member 68 is pointed downward, the cables instead make contactwith the relatively smooth surfaces of the top and side surfaces 72,74,thereby protecting the cables from damage. In this regard, in at leastone alternative embodiment (not illustrated), the channel member 68 maybe replaced by an arcuate member that provides a minimum radius ofcurvature, thereby preventing cables from being bent unnecessarily.

The air diverter 60 further includes a pair of connection tabs 78disposed on the wing elements 80 thereof. The wing elements 80 aregenerally positioned at a height corresponding to the elevation of thelowermost horizontal mounting rail 28 within the enclosure 10, and thetabs 78 therefore provide a means for the air diverter 60 to beconnected to a pair of horizontal mounting rails 28 of the enclosure 10using the mounting rail slots, described previously and visible in FIG.7. Further, any known connection means may be used to connect the airdiverter 60 to the bottom panel 36 of the enclosure 10 as desired.

Notably, although not shown, because the wing elements 80 extend outfrom the side edges of the air diverter 60, the vertical mounting rails30 may alternatively be disposed between the side edges of the airdiverter 60 and the horizontal mounting rails 28 in the inset areas83,85 located above and below the wing elements 80. Thus, the verticalmounting rails may be arranged by a user at nearly any location alongthe horizontal mounting rails 28 from the front to the back of theenclosure 10, other than where the wing elements 80 are present. Thelower inset area 85 also provides another function, in that cablesentering the bottom of the enclosure 10 may be routed forward almostimmediately after entering the enclosure using the space provided by thelower inset area 85. In the absence of such a space, cables would haveto be routed up and over the wing elements, thus making the cablesunnecessarily long.

In use, the ducted exhaust equipment enclosure 10 is typically, thoughnot always, installed on a raised floor 82. FIG. 11 is a rear isometricview of the ducted exhaust equipment enclosure 10 of FIG. 1, showninstalled on a raised floor 82, and FIG. 12 is a side cross-sectionalview of the ducted exhaust equipment enclosure 10 of FIG. 11, takenalong the line 11-11. The raised floor 82 includes a plurality of floorpanels or tiles 84 of standard size and conventional design, allsupported above the permanent floor at a desired height. The floor tiles84 conventionally include solid tiles as well as perforated orventilated tiles, the latter of which are designed to permit cool airsupplied from the space beneath the floor 82, commonly referred to asthe raised floor plenum, to flow therethrough. In particular, aventilated tile may be located directly in front of the enclosure 10 toprovide the most direct path to the interior of the enclosure and theair intakes for the equipment 86 located inside. Further, although notspecifically illustrated herein, the area directly underneath such anenclosure 10 is often left fully or partially open by eliminating one ormore tiles 84, by using tiles 84 with large openings therein, or byusing tiles 84 that are less than full-size.

FIG. 13 is a schematic illustration of a series of ducted exhaustequipment enclosures 10 showing cool air flowing in and hot return airflowing out. As shown in FIGS. 11 and 12, once one or more enclosures 10are installed on the raised floor 82, electronic equipment 86 isinstalled in the various equipment enclosures 10, typically by attachingthe equipment 86 to the vertical mounting rails 30, and operatednormally. As described previously, the equipment 86 generatesconsiderable thermal energy while it operates. The thermal energy iscarried by air currents which may be forced or forcibly drawn out of therear of the various active pieces of equipment 86 by internal fans (notshown), often supplemented by separate fans (not shown) mounted in or onthe enclosures 10. The air-impervious rear door 40 prevents heated airfrom escaping out the rear of the enclosure 10 where it would mix withcool air outside and be drawn back through the enclosures 10. Heated airnear the bottom of each enclosure 10 is further redirected upward by theair diverters 60. The heated air is then exhausted through the exhaustair ducts 14 as represented by arrows 90, and into the return air duct92. Once there, the heated air is handled by the CRAC, sometimes incombination with additional ducts, fans, partitions, and/or otherequipment (not shown).

At the same time, cool air, represented by arrows 94, flows up throughthe perforated tiles 84 and in through the front of the enclosure 10,thereby facilitating the flow of air through the enclosure 10 andcooling the equipment 86 mounted therein. Although not shown, cool airis often also guided through the openings directly beneath the enclosure10. Care must be taken to force such air to the front of the equipment86 to avoid letting it escape immediately up the back of the enclosure10.

Thus, the ducted exhaust equipment enclosure 10 allows the components 86stored therein to draw the required volume of air through the enclosure10, and then directs the exhaust out of and away from the enclosure 10thereby eliminating the problem of air recirculation. The ducted exhaustequipment enclosure 10 segregates hot exhaust air by directing it up anexhaust air duct 14 at the top rear of the enclosure 10. This approachdelivers enhanced cooling of components resulting in a more efficientuse of available cool air and better overall heat transfer away fromcomponents.

Preferably, and as shown in FIG. 13, the exhaust air duct 14 isconnected to a drop ceiling return air plenum. However, this is notnecessary where high ceilings can offer sufficient clearance for thereturn air to stratify above the cold air in the room.

Several benefits become obvious with this architecture. For example,enclosures 10 do not have to be oriented front-to-front and back-to-backalong hot aisle/cold aisle rows, as they do with conventional hotaisle/cold aisle arrangements. This freedom allows enclosurearrangements to be driven by other infrastructure requirements. Inaddition, up to 100% of the exposed floor can be perforated. Perforatedtiles 84 can be located anywhere in the room. Using ducted exhaustequipment enclosures 10 allows the entire data center to be cold, i.e.,no more hot zones. Cold intake air can be pulled from anywhere in theroom. An enclosure 10 no longer has to obtain all of the airflow neededfrom the raised floor tile directly in front or adjacent to it. As such,airflow balancing issues are significantly reduced, if not, alleviated.By enabling cold air to be delivered through 100% of the tile in theraised floor 82, it is contemplated that the airflow available to anygiven enclosure 10 can be doubled thereby doubling the heat loadcapacity of the enclosure 10.

It is important to note that because the ducted exhaust equipmentenclosures can be used in data centers both with raised floors 82 orwithout raised floors 82, they are extremely versatile. The ductedexhaust equipment enclosures 10 can be used in rooms with or without araised floor 82 and can be partially or completely cooled using a raisedfloor plenum or by an alternative cooling means such as ducts within adata center. Accordingly, the following scenarios are possible with theducted exhaust equipment enclosures: 1) a data center wherein cold airis supplied using only a raised floor approach, 2) a data center whereinno raised floor is present and cold air is supplied using onlyalternative approaches to a raised floor, e.g., ducts in the room, 3) adata center wherein a raised floor 82 is present but cold air issupplied by ducts in the room, and 4) a data center wherein cold air ispartially supplied by ducts in the room and partially supplied by araised floor plenum.

Use of the ducted exhaust equipment enclosures 10 also creates theopportunity to deploy high density applications in a non-raised floorenvironment because cold air can be delivered directly into the roomrather than through a raised floor. In addition, the use of ductedexhaust equipment enclosures 10 avoids any dependency on booster fans,with the accompanying concerns over additional heat loads, fan failureand redundancy, thereby reducing the cost of equipping a data center.

In the process described above, each air diverter 60 reduces oreliminates eddies that would otherwise be present in the hot return airat the bottom rear of the enclosure 10. Such eddies can cause computercomponents mounted at the bottom of the enclosure 10 to operate at ahigher temperature than components mounted higher up in the enclosure10. The air diverter 60 reduces or eliminates such eddies by turning hotreturn air upward in the direction of primary flow of hot return air. Itis contemplated that intermediate half-scoop air diverters (not shown)may also be added at various vertical spacing locations along the backof the enclosure 10. These intermediate half-scoops of various sizes andshapes may be used to further improve air flow and air balance.Advantageously, although the exhaust air duct 14 may be used by itself,the various scoops help start the vertical flow of heated air up towardthe duct 14, thereby making it function more efficiently than if used byitself.

The enclosure 10 may include additional features to aid in airflowmanagement of the enclosure 10. One such feature is the inclusion ofmetal bracket seals 88 around the connection means used to connect theback door panel 40 to the enclosure 10. The seals 88 further ensure thatexhaust air exits the enclosure 10 via the exhaust air duct 14 ratherthan through small openings around the connection means or edges of thedoor. Further, foam or rubber gaskets (not shown) may be added to, ormay replace, the metal bracket seals 88 to create a further barrier toair release.

Another contemplated feature is a brush opening in the bottom panel 36of the enclosure 10. Often an enclosure will have an opening in thebottom panel thereof for receipt of cables that provide power and otherinput or output to the components stored in the enclosure.Unfortunately, air is able to flow freely through the opening therebyaltering the intended airflow scheme of the enclosure. It is possible toinclude a plurality of bristles extending inwardly from opposing sidesof the opening such that exterior ends of the bristles are touching. Thebristles essentially cover the opening thereby preventing air fromflowing there through. In the same instance, the cables are still ableto pass through the opening by displacing the bristles for their passagethere through. Although, the brushes are not shown in FIG. 7, it iscontemplated that the cable opening 96 of the enclosure 10 will be abrush opening

Based on the foregoing information, it is readily understood by thosepersons skilled in the art that the present invention is susceptible ofbroad utility and application. Many embodiments and adaptations of thepresent invention other than those specifically described herein, aswell as many variations, modifications, and equivalent arrangements,will be apparent from or reasonably suggested by the present inventionand the foregoing descriptions thereof, without departing from thesubstance or scope of the present invention.

Accordingly, while the present invention has been described herein indetail in relation to its preferred embodiment, it is to be understoodthat this disclosure is only illustrative and exemplary of the presentinvention and is made merely for the purpose of providing a full andenabling disclosure of the invention. The foregoing disclosure is notintended to be construed to limit the present invention or otherwiseexclude any such other embodiments, adaptations, variations,modifications or equivalent arrangements; the present invention beinglimited only by the claims appended hereto and the equivalents thereof.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for the purpose of limitation.

What is claimed is:
 1. An electronic equipment enclosure, comprising:(a) a frame structure formed from a plurality of support posts and crossmembers, the frame structure having a front-to-back length and aside-to-side width; (b) a top panel mounted on the frame structure, thetop panel including: (i) a plurality of outer edges, each outer edge ofthe plurality of outer edges partially defining a perimeter of the toppanel, the perimeter having a front-to-back length and a side-to-sidewidth, wherein each outer edge is generally perpendicular to two otherouter edges, (ii) a plurality of inner edges that define a rectangularopening in the top panel, the rectangular opening having a front-to-backlength and a side-to-side width, wherein each inner edge of theplurality of inner edges is generally parallel to two outer edges, and(iii) wherein the side-to-side width of the rectangular opening is atleast 85% of the side-to-side width of the top panel perimeter; (c) sidepanels and a back panel mounted on the frame structure and, togetherwith the top panel, at least partially enclosing the frame structure anddefining a single compartment in which an electronic component ismounted; and (d) an exhaust air duct, extending upward from the toppanel, wherein: (i) at least a lower section of the exhaust air duct isrectangular in cross-section that is defined by four panels havingsmooth interior surfaces and intersecting each other at right angles,the cross-section having a front-to-back length and a side-to-sidewidth, (ii) the front-to-back length of the exhaust air ductcross-section is substantially the same as the front-to-back length ofthe top panel rectangular opening, (iii) the side-to-side width of theexhaust air duct cross-section is substantially the same as theside-to-side width of the top panel rectangular opening, and (iv) thelower section of the exhaust air duct is disposed in surroundingrelation to, and in fluid communication with, the top panel opening suchthat the panels of the lower section of the exhaust air duct aredirectly aligned with the inner edges of the top panel and an interiorof the exhaust air duct is in direct and unobstructed fluidcommunication with the interior of the single compartment; (e) whereinhot air from the electronic component travels vertically, within thesingle compartment, to the rectangular top panel opening without passingthrough the back panel of the compartment; and (f) wherein the exhaustair duct is adapted to segregate hot air being exhausted from thecompartment from cool air entering the compartment, thereby improvingthermal management of the enclosure.
 2. The electronic equipmentenclosure of claim 1, wherein the rectangular top panel opening isdisposed toward the rear of the compartment.
 3. The electronic equipmentenclosure of claim 2, wherein the rectangular top panel opening isdisposed entirely in a rear half of the top panel.
 4. The electronicequipment enclosure of claim 3, wherein the front-to-back length of therectangular opening is at least 45% of the front-to-back length of thetop panel perimeter.
 5. The electronic equipment enclosure of claim 2,wherein a distance from a rear of the rectangular opening and a rear ofthe top panel is from 0% to 3% of the front-to-back length of the toppanel.
 6. The electronic equipment enclosure of claim 2, wherein one ormore access openings are disposed in a front half of the top panel. 7.The electronic equipment enclosure of claim 6, wherein the accessopening include cable openings.
 8. The electronic equipment enclosure ofclaim 7, wherein the cable openings are rectangular brush openings. 9.The electronic equipment enclosure of claim 1, wherein the back panel isgenerally air-impervious to prevent heated air from escapingtherethrough.
 10. The electronic equipment enclosure of claim 1, whereinthe side-to-side width of the exhaust air duct is selected to correspondto the width of the enclosure such that the width is as wide as possibleand still be mountable to the top of the enclosure.
 11. The electronicequipment enclosure of claim 1, wherein the panels of the exhaust airduct are constructed of a smooth, stiff material.
 12. The electronicequipment enclosure of claim 1, wherein the lower section of the exhaustair duct has a bottom opening that is substantially the same size andshape as a size and shape of the rectangular opening of the top panel.13. The electronic equipment enclosure of claim 1, wherein a respectivenarrow portion of the top panel extends along each side of therectangular opening.
 14. The electronic equipment enclosure of claim 13,wherein the exhaust air duct is attached to the respective narrowportions of the top panel via mounting flanges attached directlythereto.
 15. The electronic equipment enclosure of claim 1, wherein anair plenum is defined by an interior of the back panel, interiors of theside panels, and a rear of equipment mounted in the enclosure, whereinthe air plenum extends vertically within the enclosure, wherein the airplenum has a side-to-side width, and wherein the side-to-side width ofthe rectangular opening is substantially as wide as the side-to-sidewidth of the air plenum.
 16. The electronic equipment enclosure of claim15, wherein the air plenum has a front-to-back length, and wherein thefront-to-back length of the rectangular opening is substantially as longas the front-to-back length of the air plenum.
 17. The electronicequipment enclosure of claim 15, wherein the side-to-side width of theexhaust air duct is substantially as wide as the side-to-side width ofthe air plenum.
 18. An electronic equipment enclosure, comprising: (a) aframe structure formed from a plurality of support posts and crossmembers, the frame structure having a front-to-back length and aside-to-side width; (b) a top panel mounted on the frame structure, thetop panel including: (i) a plurality of outer edges, each outer edge ofthe plurality of outer edges partially defining a perimeter of the toppanel, the perimeter having a front-to-back length and a side-to-sidewidth, wherein each outer edge is generally perpendicular to two otherouter edges, (ii) a plurality of inner edges that define a rectangularopening in the top panel, the rectangular opening having a front-to-backlength and a side-to-side width, wherein each inner edge of theplurality of inner edges is generally parallel to two outer edges, and(iii) wherein the side-to-side width of the rectangular opening is atleast 85% of the side-to-side width of the top panel perimeter; and (c)side panels and a back panel mounted on the frame structure and,together with the top panel, at least partially enclosing the framestructure and defining a single compartment in which an electroniccomponent is mounted; (d) wherein an air plenum is defined by aninterior of the back panel, interiors of the side panels, and a rear ofequipment mounted in the enclosure, wherein the air plenum extendsvertically within the enclosure, wherein the air plenum has aside-to-side width, and wherein the side-to-side width of therectangular opening in the top panel is substantially as wide as theside-to-side width of the air plenum; (e) wherein hot air from theelectronic component travels vertically, within the single compartment,to the rectangular top panel opening without passing through the backpanel of the compartment; and (f) wherein the rectangular opening in thetop panel is adapted to segregate hot air being exhausted from thecompartment from cool air entering the compartment, thereby improvingthermal management of the enclosure.
 19. The electronic equipmentenclosure of claim 18, wherein a respective narrow portion of the toppanel extends along each side of the rectangular opening.
 20. Theelectronic equipment enclosure of claim 19, wherein an exhaust air ductis attached to the respective narrow portions of the top panel viamounting flanges attached directly thereto.